beta-hCG as a diagnostic aid for suspected ectopic pregnancy

During 13 months from November 1, 1977, through November 30, 1978, 283 patients underwent radioimmunoassay (RIA) for determination of serum beta-subunit of human chorionic gonadotropin (beta-hCG) to rule out ectopic pregnancy. The records of 234 patients were available for statistical analysis and of these, 188 (80%) had negative results, defined as less than 1 ng/ml. The ectopic group comprised 22 patients, all of whom had elevated beta-hCG levels. There were no false-negative results in either group. Patients with suspected ectopic pregnancy had symptoms similar to patients previously reported in the literature with proved ectopic pregnancies. The most common presenting symptoms of those with suspected ectopic pregnancy were abdominal pain (91%), amenorrhea (76%), irregular bleeding (68%), and andexal mass (55%). Seventy-three patients presented with the classic triad of pain, uterine bleeding, and adnexal mass. Only 10 (14%) had ectopic pregnancies. Urine pregnancy tests were found to be of no benefit in diagnosing ectopic pregnancy and confused the clinicians in some instances. In patients with suspected ectopic pregnancy, a negative beta-hCG, by the RIA technique ruled out ectopic pregnancy in 100% of the cases.